The present invention relates to projection television systems, and more particularly, to a molded plastic television cabinet having reference features molded into one part for aligning the critical optical components of the projection television system.
A conventional projection television (TV) system typically consists of a plurality of critical optical components mounted in a multi-part cabinet structure. The optical components commonly include a light projector assembly for generating television images, a screen for viewing the images, and a large mirror (often combined with a smaller mirror) for directing the images generated by the light projector assembly to the screen. The multi-part cabinet structure usually includes a front section having a screen frame that mounts the screen, a rear section or back cover which mounts the large mirror, a first bracket for mounting the small mirror, and a second bracket for mounting the light projector assembly to the cabinet front section.
Each optical component/cabinet part interface adds tolerance stack to the TV system. In some designs, the large mirror is mounted to a multi-piece sheet metal structure that is mounted to the cabinet front section along with the light projector assembly and the screen. The use of such a multi-piece sheet metal structure to hold the large mirror adds additional tolerance stack into the TV system.
Increased tolerance stack in the location of the critical optical components, undesirably increases geometric distortions of the television images and requires an increased range of adjustment of the optical components to correct these distortions. Accordingly, a cabinet structure is needed that limits the tolerance stack so that minimal or no adjustment is necessary to obtain acceptable geometry.